Phase shift in transmitted electrocardiograms: a cautionary tale of distorted signals.

We describe how a routine manufacturer's upgrade of equipment designed to record and transmit electrocardiograms inadvertently introduced the potential for artefact that simulated the ST segment elevation of myocardial infarction. Whilst this type of artefact from a phenomenon known as phase shift is likely to be rare, the possibility should be recognised. Any doubt about the veracity of ST segment elevation from this phenomenon can be tested by introducing test signals from a simple pulse generator.

The importance of assessing the fidelity of electrocardiographs by using a simple calibration signal.

ECG distortion, mimicking changes seen in acute myocardial infarction, occurred in traces transmitted by the South East Coast NHS Ambulance Trust. This was due to low frequency phase nonlinearity produced by baseline filtering. The very narrow calibration pulses made the detection of this distortion difficult.

A prospective audit of pacemaker function, implant lifetime, and cause of death in the patient.

Aim: To audit prospectively the reasons for pacemaker implantation, the duration of the pacemaker use, the cause of death, and pacemaker function after removal from the patient.

Methods: Pacemakers were removed at necropsy, or from the bodies of patients awaiting cremation, in three hospitals over a three year period. The cause of death was taken from the results of the necropsy or from the certified cause of death.

Ultrasound enhances reporter gene expression after transfection of vascular cells in vitro.

Background: Restenosis after percutaneous coronary intervention remains a serious clinical problem. Progress in local gene therapy to prevent restenosis has been hindered by concerns over the safety and efficacy of viral vectors and the limited efficiency of nonviral techniques. This study investigates the use of adjunctive ultrasound to enhance nonviral gene delivery.